Electrical field stimulation (EFS) of rabbit ileum mounted in a flux chamber increases the luminal electrical negativity, increases the short circuit current, reduces tissue total ionic conductance, and causes chloride secretion. Similar changes may be caused by scorpion venom (Leiurus quinquestriatus) which depolarizes nerves; the responses to EFS may be prevented by agents which interfere with neural transmission, viz, scorpion venom, veratrine, 50 mM K, and tetrodotoxin. The identity of the chemical transmitter is not known, but it is clear that the response requires calcium in the bathing medium. We plan studies to determine: 1) the identity of the chemical transmitter by determining if the response can be prevented with antibodies to Vasoactive Intestinal Peptide, or to Substance P; 2) the role of the paracellular shunt in mediating the secretory changes caused by EFS; and 3) the effects of EFS on other epithelia of the alimentary canal, including that obtained from the colon and small intestine of patients from whom the tissues are being resected.